Generally, a vibrating actuator fitted to a portable electronic device is provided with a coil for current application, a diaphragm fastened at one side of the coil, a magnet to form a magnetic circuit, a magnetic yoke supporting this magnet, and an oscillation plate that supports this magnetic yoke. A diaphragm is mounted within the frame of a case by a lip with a magnetic gap between the coil and the magnetic yoke, and an oscillation plate is mounted within the frame of the case at an edge. A cover over the mounting side of an oscillation plate is fitted to the case. Vibration is generated from the oscillation plate at low frequency by the action of current applied to a coil and a magnetic field of a magnet while a sound is issued from the diaphragm at high frequency.
This type of vibrating actuator must have high impact resistance so that it does not break even if dropped by a user. A means of imparting such impact resistance is to mount a projection from the side wall of the case to the interior to function as a stopper that contacts the magnetic yoke should it swing violently due to impact.
Expansion of the frame diameter of the case is inhibited to the extent that a projection is mounted in this vibrating actuator, and a comparatively thick magnetic yoke is provided because of the need to ensure a weight sufficient to actuate the oscillation plate. Consequently, actuators are limited to thin ones.
Furthermore, when impact is applied, it is transmitted from the cover to the oscillation plate, causing the oscillation plate to deform which causes noise due to abnormal vibration.
In addition, the coil and the power supply section of the circuit board are connected by using a flexible cord as the wiring that applies current to the coil, but even if they are connected by this flexible cord, there is a fear of disconnection of the flexible cord at the connection terminal because of the application of a load to the connection terminal of the lead line accompanying vibration during operation.
An expansion of the utility of aforementioned vibrating actuator is desired as a product by altering the acoustic characteristics at a given frequency band.